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Keywords

Globular cluster; metal poor star; H-burning; abundance.

Abstract

The origin of the abundance pattern and also the (anti)correlation present among the elements found in stars of globular clusters (GCs) remains unimproved until date. The proton-capture reactions are presently recognised in concert of the necessary candidates for that sort of observed behaviour in the second generation stars. We tend to propose a reaction network of a nuclear cycle namely carbon–nitrogen–oxygen–fluorine (CNOF) at evolved stellar condition since fluorine (19F) is one such element which gets plagued by proton capture reactions. The stellar temperature thought about here ranges from 2×107 to 10×107 K and there has been an accretion occuring, with material density being 102 g/cm3 and 103 g/cm3. Such kind of temperature density conditions are probably going to be prevailing within the H-burning shell of evolved stars. The estimated abundances of 19F are then matched with the info that has been determined for a few some metal-poor giants of GC M4, M22,47 Tuc as well as NGC 6397. As far as the comparison between the observed and calculated abundances is concerned, it is found that the abundance of 19F have shown an excellent agreement with the observed abundances with a correlation coefficent above 0.9, supporting the incidence of that nuclear cycle at the adopted temperature density conditions.

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Posted on January 27, 2016

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